In a principal aspect the present invention relates to an automotive repair tool, and more particularly, a tool for compressing the caliper pistons of a vehicle disc brake assembly so that the disc pads may be removed and replaced. The invention thus comprises a manually actuated disc pad spreading tool which may be utilized for disc brake assemblies having one or multiple pistons associated with the disc brake caliper assembly.
Disc brakes typically include a caliper housing which is mounted adjacent a wheel. The housing includes opposed disc pads which are piston driven toward one another for clamping a rotating disc associated with a rotating wheel of the vehicle to brake or stop the vehicle. From time to time it is necessary to replace the pads due to the fact that they wear as a result of frictional contact with the rotating disc. In such circumstances, the caliper housing is typically removed from the wheel assembly of the vehicle. The outboard pad may then be removed and the inboard disc pad mounted in the housing may be caused to be spread apart by retracting the pad driving piston or pistons into the caliper housing. Alternatively, both pads may be engaged by a spreading tool to effect separation of the worn pads. The pistons which have been pushed back allow adequate room for installation of new pads. The caliper housing may then be replaced in the wheel assembly and positioned for engagement with the brake disc.
Heretofore, applicant's assignee has secured patent coverage with respect to automotive or vehicle repair tools useful with respect to the replacement of disc pads in a disc brake assembly. In particular, U.S. Pat. No. 6,874,217 issued Apr. 5, 2005 entitled “Disc Brake Pad Spreading Tool” describes one such tool. The aforesaid patent is incorporated herewith by reference in its entirety. Further, U.S. Pat. No. 7,076,850 issued Jul. 18, 2006 entitled “Dual Piston Disc Brake Caliper Compressor” discloses another tool having a similar function. The aforesaid patent is also incorporated herewith by reference. While such tools are deemed useful, the continued development and improvement of disc brake assemblies has resulted in the design of disc brake calipers having multiple pistons. For example, U.S. Pat. No. 7,076,850 referenced herein was especially designed for use with a dual piston disc brake assembly. Recently, however, automotive and vehicle manufacturers have increased the number of pistons associated with a caliper for a disc brake. For example, four pistons, and in some instances six pistons, have been incorporated in new designs.
Thus, there has developed a need for an improved disc brake spreading tool which can separate worn disc pads and retract multiple pistons simultaneously.